A parallax barrier 3D display device comprises a display panel (e.g., a liquid crystal display (LCD) panel) and a parallax bather disposed in front of the display panel or disposed in parallel between the LCD panel and a backlight. The 3D display device alternately displays a left-eye image and a right-eye image on the basis of pixel columns of the display panel in display, and allows a left eye and a right eye to respectively view the left-eye image and the right-eye image displayed in pixels of the display panel by means of the shielding function of the grating sheets of the parallax barrier. More specifically, one frame of 3D image includes two images which are respectively the left-eye image and the right-eye image. When a glasses-free 3D display device displays the 3D image, generally, one part of pixels are adopted to display the left-eye image and the other part of pixels are adopted to display the right-eye image. The left-eye image and the right-eye image are respectively projected to the visible ranges of the left eye and the right eye. The left eye and the right eye of the viewer respectively view the left-eye image and the right-eye image, and hence a 3D display image is produced in the brain of the viewer.
The parallax barrier of the glasses-free parallax barrier 3D display device mainly adopts a slit grating, e.g., a slit grating structure as shown in FIG. 1. As the black matrix (BM) of the display panel and the grating array of the slit grating have different grating pitches, interference will occur when light emitted by each sub-pixel of the display device passes through the black matrix and the grating array, and hence alternately dark and bright stripes as shown in FIG. 1, namely Moire fringes, will be produced. In this situation, the viewer will view severe Moire phenomenon, and hence the 3D display effect can be disadvantageously affected.